The words "In God We Trust," a controversial phrase that some argue should be kept off of our currency, has appeared on all forms of U.S. money since 1963, although the history behind the motto dates back much further.

In 1861, Rev. M. R. Watkinson, a Pennsylvania minister, wrote to Secretary of Treasury Salmon P. Chase pleading that new coin designs include "the recognition of the Almighty God," according to Treasury Department records.

Chase was so moved by Watkinson's letter that he requested that the U.S. Mint prepare a motto that would sum up the growing religious sentiment during the Civil War era in "the fewest and tersest words possible."

"The trust of our people in God should be declared on our national coins," Chase wrote in a letter to the Director of the U.S. Mint at Philadelphia.

On April 22, 1864, Congress passed a law requiring that one-cent, two-cent and three-cent coins include the phrase. Later that year, "In God We Trust" first appeared on the two-cent coin.

The law that put the motto on paper currency was passed in 1955, Claudia Dickens, a spokesperson for the U. S. Bureau of Engraving and Printing, told Life's Little Mysteries.

In 1956, Congress passed an act that made "In God We Trust" the official national motto of the United States.

Over the years, people have argued against the presence of the religious motto on American currency. President Theodore Roosevelt, in a letter published in the New York Times in 1907, wrote that keeping the motto on coins was unwarranted and possibly sacrilegious.

"My own feelings in the matter is due to my very firm conviction that to put such a motto on coins, or to use it in any kindred manner, not only does no good, but does positive harm, and is in effect irreverence, which comes dangerously close to sacrilege," Roosevelt wrote.

In response to the first court case challenging the motto, the 9th U.S. Circuit Court of Appeals ruled in 1970 that "its use is of patriotic or ceremonial character and bears no true resemblance to a governmental sponsorship of a religious exercise." The Supreme Court of the United States declined to review the case.

Since then, the motto has been repeatedly challenged in federal courts, but it has not been found to violate the First Amendment's prohibition of the establishment of religion.